Reuters: British energy giant BP Plc’s stock price tumbled on Wednesday as it faced more U.S. government and congressional scrutiny over its handling of the massive Gulf of Mexico oil spill. BP shares fell around 6 percent in London, following a 5 percent drop on Tuesday, on worries that the company will have to suspend its dividend payment under pressure from U.S. politicians who say it should go to pay for legal claims and environmental damage in the Gulf. The cost of protecting BP …